Changeset 286793 in webkit

Timestamp:

Dec 9, 2021, 11:53:55 AM (5 years ago)

Author:

Alan Coon

Message:

Apply patch. rdar://problem/86235842

Location:

branches/safari-612-branch/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• page/scrolling/ScrollingTree.h (modified) (2 diffs)
• page/scrolling/mac/ScrollingTreeScrollingNodeDelegateMac.h (modified) (1 diff)
• page/scrolling/mac/ScrollingTreeScrollingNodeDelegateMac.mm (modified) (3 diffs)

branches/safari-612-branch/Source/WebCore/ChangeLog

@@ +1 @@
+2021-12-09  Alan Coon  <alancoon@apple.com>
+
+        Apply patch. rdar://problem/86235842
+
+    2021-12-09  Simon Fraser  <simon.fraser@apple.com>
+
+            rdar://86235842 ([root] J316c: Rubber-banding is more stuttery with the momentum generator enabled)
+
+            Reviewed by Tim Horton.
+
+            Branch-only patch (this timer does not exist on trunk).
+
+            To avoid raciness between displayDidRefresh callbacks and the rubberbanding timer, offset
+            the timer by 1/4 frame. After the first frame, we reset its fire interval back to the
+            nominal frame rate.
+
+            stopAnimationCallback() sets m_isAnimationTimerInOffsetPhase to false to avoid any chance
+            of restarting a stopped timer in the callback.
+
+            * page/scrolling/ScrollingTree.h:
+            * page/scrolling/mac/ScrollingTreeScrollingNodeDelegateMac.h:
+            * page/scrolling/mac/ScrollingTreeScrollingNodeDelegateMac.mm:
+            (WebCore::ScrollingTreeScrollingNodeDelegateMac::startAnimationCallback):
+            (WebCore::ScrollingTreeScrollingNodeDelegateMac::stopAnimationCallback):
+            (WebCore::ScrollingTreeScrollingNodeDelegateMac::scrollControllerAnimationTimerFired):
+
 2021-12-03  Alan Coon  <alancoon@apple.com>
 

branches/safari-612-branch/Source/WebCore/page/scrolling/ScrollingTree.h

@@ -224 +224 @@
     void windowScreenDidChange(PlatformDisplayID, std::optional<FramesPerSecond> nominalFramesPerSecond);
     PlatformDisplayID displayID();
-    
+
+    std::optional<FramesPerSecond> nominalFramesPerSecond();
+
     bool hasProcessedWheelEventsRecently();
     WEBCORE_EXPORT void willProcessWheelEvent();
@@ -258 +260 @@
     std::optional<WheelScrollGestureState> gestureState();
 
-    std::optional<FramesPerSecond> nominalFramesPerSecond();
-
     void applyLayerPositionsInternal() WTF_REQUIRES_LOCK(m_treeLock);
     void removeAllNodes() WTF_REQUIRES_LOCK(m_treeLock);

branches/safari-612-branch/Source/WebCore/page/scrolling/mac/ScrollingTreeScrollingNodeDelegateMac.h

@@ -111 +111 @@
 
     std::unique_ptr<RunLoop::Timer<ScrollingTreeScrollingNodeDelegateMac>> m_scrollControllerAnimationTimer;
+    bool m_isAnimationTimerInOffsetPhase { false };
 
     bool m_inMomentumPhase { false };

branches/safari-612-branch/Source/WebCore/page/scrolling/mac/ScrollingTreeScrollingNodeDelegateMac.mm

@@ -29 +29 @@
 #if ENABLE(ASYNC_SCROLLING) && PLATFORM(MAC)
 
+#import "AnimationFrameRate.h"
 #import "Logging.h"
 #import "ScrollingStateScrollingNode.h"
@@ -230 +231 @@
         return;
 
-    m_scrollControllerAnimationTimer->startRepeating(1_s / 60.);
+    // We offset the timer by a 1/4 frame to avoid it racing with displayDidRefresh callbacks (rdar://86235842).
+    auto framesPerSecond = scrollingTree().nominalFramesPerSecond().value_or(FullSpeedFramesPerSecond);
+    auto firstInterval = (1_s / framesPerSecond) / 4;
+    m_isAnimationTimerInOffsetPhase = true;
+    m_scrollControllerAnimationTimer->startRepeating(firstInterval);
 }
 
 void ScrollingTreeScrollingNodeDelegateMac::stopAnimationCallback(ScrollController&)
 {
+    m_isAnimationTimerInOffsetPhase = false;
     if (m_scrollControllerAnimationTimer)
         m_scrollControllerAnimationTimer->stop();
@@ -241 +247 @@
 void ScrollingTreeScrollingNodeDelegateMac::scrollControllerAnimationTimerFired()
 {
+    if (m_scrollControllerAnimationTimer && m_isAnimationTimerInOffsetPhase) {
+        auto framesPerSecond = scrollingTree().nominalFramesPerSecond().value_or(FullSpeedFramesPerSecond);
+        m_scrollControllerAnimationTimer->startRepeating(1_s / framesPerSecond);
+        m_isAnimationTimerInOffsetPhase = false;
+    }
+
     m_scrollController.animationCallback(MonotonicTime::now());
 }